1. Field of Invention
The present invention relates to a printer that communicates with an external device through an interface device, and relates more particularly to a printer that can effectively handle problems caused by static electricity in the interface device.
2. Description of Related Art
Printers are often used while connected over a network to the host device that sends print requests to the printer. In such situations, an interface device that controls the communication interface between the printer and the host device or other external device is disposed in the printer or separately from the printer, and the printer and external device communicate through the interface device.
Printers also use consumables such as ink, toner, or other color material and a print medium such as paper, and these consumables are replaced as needed by the user. Replacing the consumables typically involves opening a printer cover and performing some operation inside the printer, at which time the user may touch metal parts inside the printer. This poses the danger of static electricity from the user's body being discharged to the metal part, which can cause such problems as rendering the interface device nonfunctional.
To prevent this, parts that might be touched by the user may be grounded. Japanese Unexamined Patent Appl. Pub. JP-A-H05-221085, for example, teaches a structure for passing static electricity discharged from the user's body to ground by connecting a switch that is touched by the user to the ground terminal of the frame.
Such conventional hardware solutions cannot completely prevent problems caused by static electricity, however, and an effective solution for when problems occur is not disclosed. The danger of problems due to static electricity thus remains with conventional interface devices, and great financial and other types of losses may be incurred until the interface device can be restored once such a problem occurs and the interface device stops functioning.